1. Field of the Invention
The present invention relates to a control apparatus for a reactive power compensation apparatus for suppressing voltage fluctuations in a power system.
2. Description of the Related Art
In such a conventional reactive power compensation apparatus, in order to improve a transient response of a control system in terms of stability and speed, gain K.sub.p (=(1+TpS)/TpS) of the reactive power determining circuit (PI control circuit) is optimized in accordance with the value of power source impedance Z. However, the value of power source impedance Z is not constant and is greatly changed depending on a condition in which the power system is used. For example, the value of power source impedance Z is changed due to, e.g., a difference in condition between day and night and between seasons, and variations in condition caused by additional installation of a power plant. For this reason, if power source impedance Z is reduced under constant gain Kp, the gain of the control loop is decreased to cause a decrease in transient response speed. In contrast to this, if power source impedance Z is increased, the gain of the control loop is increased, resulting in an unstable response and hunting.